feat: gravity transaction logging + user-facing history popup
- New GravityTransaction schema tracks all gravity changes (registration,
interview/optimize/download deduction, purchase, monthly topup, migration)
- GravityTopUpService: bulk log for monthly VIP topup
- PaymentController.activateMembership: log plan_set transactions
- QuotaService: add logTransaction, wire into all gravity-modifying methods
- UserService: log registration grants (phone/wx/email/password)
- GET /user/gravity-transactions?page=&limit= API
- Frontend: user.vue '明细' button + paginated popup
- Docs: update PROJECT-STATUS v4.10, FEATURE-LIST, DEPLOYMENT
yuzhiran
2230a95b45